take_screenshot

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the burden of disclosing behavior. It mentions the use of CDP Page.getLayoutMetrics and Page.captureScreenshot for full-page capture, and explains the default viewport behavior. It could also state the return format (e.g., base64) but the core behaviors are disclosed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is extremely concise: two sentences, front-loaded with the primary purpose. It avoids redundancy and every clause adds value, explaining the default and full-page modes efficiently.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple screenshot tool, the description covers the main actions and behavioral nuances. It does not mention the return value format or whether the page must be active, but given the low complexity and helpful sibling context (e.g., ensure_active_tab), it is reasonably complete. A 4 reflects the minor gap around output specifics.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already provides complete descriptions for both parameters (page and fullPage), including the key distinction for fullPage. The description essentially repeats the fullPage behavior but adds no new meaning beyond what the schema already specifies, so a baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: 'Take a PNG screenshot of the current page.' It specifies the output format (PNG) and the resource (current page). It also distinguishes between default viewport capture and full-page capture, which differentiates it from any potential siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear usage context by explaining the default behavior (visible viewport) and when to use fullPage=true. It does not explicitly mention alternatives or when not to use the tool, but the context is sufficient for straightforward usage.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.